/* $begin csapp.c */
#include "csapp.h"

/**************************
* Error-handling functions
**************************/
/* $begin errorfuns */
/* $begin unixerror */
void unix_error(char *msg) /* unix-style error */
{
	fprintf(stderr, "%s: %s\n", msg, strerror(errno));
	exit(0);
}
/* $end unixerror */

void posix_error(int code, char *msg) /* posix-style error */
{
	fprintf(stderr, "%s: %s\n", msg, strerror(code));
	exit(0);
}

void dns_error(char *msg) /* dns-style error */
{
	fprintf(stderr, "%s: DNS error %d\n", msg, h_errno);
	exit(0);
}

void app_error(char *msg) /* application error */
{
	fprintf(stderr, "%s\n", msg);
	exit(0);
}
/* $end errorfuns */

/*********************************************
* Wrappers for Unix process control functions
********************************************/

/* $begin forkwrapper */
pid_t Fork(void)
{
	pid_t pid;

	if ((pid = fork()) < 0)
		unix_error("Fork error");
	return pid;
}
/* $end forkwrapper */

void Execve(const char *filename, char *const argv[], char *const envp[])
{
	if (execve(filename, argv, envp) < 0)
		unix_error("Execve error");
}

/* $begin wait */
pid_t Wait(int *status)
{
	pid_t pid;

	if ((pid = wait(status)) < 0)
		unix_error("Wait error");
	return pid;
}
/* $end wait */

pid_t Waitpid(pid_t pid, int *iptr, int options)
{
	pid_t retpid;

	if ((retpid = waitpid(pid, iptr, options)) < 0)
		unix_error("Waitpid error");
	return(retpid);
}

/* $begin kill */
void Kill(pid_t pid, int signum)
{
	int rc;

	if ((rc = kill(pid, signum)) < 0)
		unix_error("Kill error");
}
/* $end kill */

void Pause()
{
	(void)pause();
	return;
}

unsigned int Sleep(unsigned int secs)
{
	unsigned int rc;

	if ((rc = sleep(secs)) < 0)
		unix_error("Sleep error");
	return rc;
}

unsigned int Alarm(unsigned int seconds) {
	return alarm(seconds);
}

void Setpgid(pid_t pid, pid_t pgid) {
	int rc;

	if ((rc = setpgid(pid, pgid)) < 0)
		unix_error("Setpgid error");
	return;
}

pid_t Getpgrp(void) {
	return getpgrp();
}

/************************************
* Wrappers for Unix signal functions
***********************************/

/* $begin sigaction */
handler_t *Signal(int signum, handler_t *handler) /* 用于注册信号处理函数 */
{
	struct sigaction action, old_action;

	action.sa_handler = handler;
	sigemptyset(&action.sa_mask); /* block sigs of type being handled */
	action.sa_flags = SA_RESTART; /* restart syscalls if possible */

	if (sigaction(signum, &action, &old_action) < 0)
		unix_error("Signal error");
	return (old_action.sa_handler);
}
/* $end sigaction */

void Sigprocmask(int how, const sigset_t *set, sigset_t *oldset)
{
	if (sigprocmask(how, set, oldset) < 0)
		unix_error("Sigprocmask error");
	return;
}

void Sigemptyset(sigset_t *set)
{
	if (sigemptyset(set) < 0)
		unix_error("Sigemptyset error");
	return;
}

void Sigfillset(sigset_t *set)
{
	if (sigfillset(set) < 0)
		unix_error("Sigfillset error");
	return;
}

void Sigaddset(sigset_t *set, int signum)
{
	if (sigaddset(set, signum) < 0)
		unix_error("Sigaddset error");
	return;
}

void Sigdelset(sigset_t *set, int signum)
{
	if (sigdelset(set, signum) < 0)
		unix_error("Sigdelset error");
	return;
}

int Sigismember(const sigset_t *set, int signum)
{
	int rc;
	if ((rc = sigismember(set, signum)) < 0)
		unix_error("Sigismember error");
	return rc;
}


/********************************
* Wrappers for Unix I/O routines
********************************/

int Open(const char *pathname, int flags, mode_t mode)
{
	int rc;

	if ((rc = open(pathname, flags, mode))  < 0)
		unix_error("Open error");
	return rc;
}

ssize_t Read(int fd, void *buf, size_t count)
{
	ssize_t rc;

	if ((rc = read(fd, buf, count)) < 0)
		unix_error("Read error");
	return rc;
}

ssize_t Write(int fd, const void *buf, size_t count)
{
	ssize_t rc;

	if ((rc = write(fd, buf, count)) < 0)
		unix_error("Write error");
	return rc;
}

off_t Lseek(int fildes, off_t offset, int whence)
{
	off_t rc;

	if ((rc = lseek(fildes, offset, whence)) < 0)
		unix_error("Lseek error");
	return rc;
}

void Close(int fd)
{
	int rc;

	if ((rc = close(fd)) < 0)
		unix_error("Close error");
}

int Select(int  n, fd_set *readfds, fd_set *writefds,
	fd_set *exceptfds, struct timeval *timeout)
{
	int rc;

	if ((rc = select(n, readfds, writefds, exceptfds, timeout)) < 0)
		unix_error("Select error");
	return rc;
}

int Dup2(int fd1, int fd2)
{
	int rc;

	if ((rc = dup2(fd1, fd2)) < 0)
		unix_error("Dup2 error");
	return rc;
}

void Stat(const char *filename, struct stat *buf)
{
	if (stat(filename, buf) < 0)
		unix_error("Stat error");
}

void Fstat(int fd, struct stat *buf)
{
	if (fstat(fd, buf) < 0)
		unix_error("Fstat error");
}

/***************************************
* Wrappers for memory mapping functions
***************************************/
void *Mmap(void *addr, size_t len, int prot, int flags, int fd, off_t offset)
{
	void *ptr;

	if ((ptr = mmap(addr, len, prot, flags, fd, offset)) == ((void *)-1))
		unix_error("mmap error");
	return(ptr);
}

void Munmap(void *start, size_t length)
{
	if (munmap(start, length) < 0)
		unix_error("munmap error");
}

/***************************************************
* Wrappers for dynamic storage allocation functions
***************************************************/

void *Malloc(size_t size)
{
	void *p;

	if ((p = malloc(size)) == NULL)
		unix_error("Malloc error");
	return p;
}

void *Realloc(void *ptr, size_t size)
{
	void *p;

	if ((p = realloc(ptr, size)) == NULL)
		unix_error("Realloc error");
	return p;
}

void *Calloc(size_t nmemb, size_t size)
{
	void *p;

	if ((p = calloc(nmemb, size)) == NULL)
		unix_error("Calloc error");
	return p;
}

void Free(void *ptr)
{
	free(ptr);
}

/******************************************
* Wrappers for the Standard I/O functions.
******************************************/
void Fclose(FILE *fp)
{
	if (fclose(fp) != 0)
		unix_error("Fclose error");
}

FILE *Fdopen(int fd, const char *type)
{
	FILE *fp;

	if ((fp = fdopen(fd, type)) == NULL)
		unix_error("Fdopen error");

	return fp;
}

char *Fgets(char *ptr, int n, FILE *stream)
{
	char *rptr;

	if (((rptr = fgets(ptr, n, stream)) == NULL) && ferror(stream))
		app_error("Fgets error");

	return rptr;
}

FILE *Fopen(const char *filename, const char *mode)
{
	FILE *fp;

	if ((fp = fopen(filename, mode)) == NULL)
		unix_error("Fopen error");

	return fp;
}

void Fputs(const char *ptr, FILE *stream)
{
	if (fputs(ptr, stream) == EOF)
		unix_error("Fputs error");
}

size_t Fread(void *ptr, size_t size, size_t nmemb, FILE *stream)
{
	size_t n;

	if (((n = fread(ptr, size, nmemb, stream)) < nmemb) && ferror(stream))
		unix_error("Fread error");
	return n;
}

void Fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream)
{
	if (fwrite(ptr, size, nmemb, stream) < nmemb)
		unix_error("Fwrite error");
}


/****************************
* Sockets interface wrappers
****************************/

int Socket(int domain, int type, int protocol)
{
	int rc;

	if ((rc = socket(domain, type, protocol)) < 0)
		unix_error("Socket error");
	return rc;
}

void Setsockopt(int s, int level, int optname, const void *optval, int optlen)
{
	int rc;

	if ((rc = setsockopt(s, level, optname, optval, optlen)) < 0)
		unix_error("Setsockopt error");
}

void Bind(int sockfd, struct sockaddr *my_addr, int addrlen)
{
	int rc;

	if ((rc = bind(sockfd, my_addr, addrlen)) < 0)
		unix_error("Bind error");
}

void Listen(int s, int backlog)
{
	int rc;

	if ((rc = listen(s, backlog)) < 0)
		unix_error("Listen error");
}

int Accept(int s, struct sockaddr *addr, socklen_t *addrlen)
{
	int rc;

	if ((rc = accept(s, addr, addrlen)) < 0)
		unix_error("Accept error");
	return rc;
}

void Connect(int sockfd, struct sockaddr *serv_addr, int addrlen)
{
	int rc;

	if ((rc = connect(sockfd, serv_addr, addrlen)) < 0)
		unix_error("Connect error");
}

/************************
* DNS interface wrappers
***********************/

/* $begin gethostbyname */
struct hostent *Gethostbyname(const char *name)
{
	struct hostent *p;

	if ((p = gethostbyname(name)) == NULL)
		dns_error("Gethostbyname error");
	return p;
}
/* $end gethostbyname */

struct hostent *Gethostbyaddr(const char *addr, int len, int type)
{
	struct hostent *p;

	if ((p = gethostbyaddr(addr, len, type)) == NULL)
		dns_error("Gethostbyaddr error");
	return p;
}

/************************************************
* Wrappers for Pthreads thread control functions
************************************************/

void Pthread_create(pthread_t *tidp, pthread_attr_t *attrp,
	void * (*routine)(void *), void *argp)
{
	int rc;

	if ((rc = pthread_create(tidp, attrp, routine, argp)) != 0)
		posix_error(rc, "Pthread_create error");
}

void Pthread_cancel(pthread_t tid) {
	int rc;

	if ((rc = pthread_cancel(tid)) != 0)
		posix_error(rc, "Pthread_cancel error");
}

void Pthread_join(pthread_t tid, void **thread_return) {
	int rc;

	if ((rc = pthread_join(tid, thread_return)) != 0)
		posix_error(rc, "Pthread_join error");
}

/* $begin detach */
void Pthread_detach(pthread_t tid) {
	int rc;

	if ((rc = pthread_detach(tid)) != 0)
		posix_error(rc, "Pthread_detach error");
}
/* $end detach */

void Pthread_exit(void *retval) {
	pthread_exit(retval);
}

pthread_t Pthread_self(void) {
	return pthread_self();
}

void Pthread_once(pthread_once_t *once_control, void(*init_function)()) {
	pthread_once(once_control, init_function);
}

/*******************************
* Wrappers for Posix semaphores
*******************************/

void Sem_init(sem_t *sem, int pshared, unsigned int value)
{
	if (sem_init(sem, pshared, value) < 0)
		unix_error("Sem_init error");
}

void P(sem_t *sem)
{
	if (sem_wait(sem) < 0)
		unix_error("P error");
}

void V(sem_t *sem)
{
	if (sem_post(sem) < 0)
		unix_error("V error");
}

/*********************************************************************
* The Rio package - robust I/O functions
**********************************************************************/
/*
* rio_readn - robustly read n bytes (unbuffered)
*/
/* $begin rio_readn */
ssize_t rio_readn(int fd, void *usrbuf, size_t n)
{
	size_t nleft = n;
	ssize_t nread;
	char *bufp = (char *)usrbuf;

	while (nleft > 0) {
		if ((nread = read(fd, bufp, nleft)) < 0) {
			if (errno == EINTR) /* interrupted by sig handler return */
				nread = 0;      /* and call read() again */
			else
				return -1;      /* errno set by read() */
		}
		else if (nread == 0)
			break;              /* EOF */
		nleft -= nread;
		bufp += nread;
	}
	return (n - nleft);         /* return >= 0 */
}
/* $end rio_readn */

/*
* rio_writen - robustly write n bytes (unbuffered)
*/
/* $begin rio_writen */
ssize_t rio_writen(int fd, void *usrbuf, size_t n)
{
	size_t nleft = n;
	ssize_t nwritten;
	char *bufp = (char *)usrbuf;

	while (nleft > 0) {
		if ((nwritten = write(fd, bufp, nleft)) <= 0) {
			if (errno == EINTR)  /* interrupted by sig handler return */
				nwritten = 0;    /* and call write() again */
			else
				return -1;       /* errno set by write() */
		}
		nleft -= nwritten;
		bufp += nwritten;
	}
	return n;
}
/* $end rio_writen */


/*
* rio_read - This is a wrapper for the Unix read() function that
*    transfers min(n, rio_cnt) bytes from an internal buffer to a user
*    buffer, where n is the number of bytes requested by the user and
*    rio_cnt is the number of unread bytes in the internal buffer. On
*    entry, rio_read() refills the internal buffer via a call to
*    read() if the internal buffer is empty.
*/
/* $begin rio_read */
static ssize_t rio_read(rio_t *rp, char *usrbuf, size_t n)
{
	int cnt;

	while (rp->rio_cnt <= 0) {  /* refill if buf is empty */
		rp->rio_cnt = read(rp->rio_fd, rp->rio_buf,
			sizeof(rp->rio_buf));
		if (rp->rio_cnt < 0) {
			if (errno != EINTR) /* interrupted by sig handler return */
				return -1;
		}
		else if (rp->rio_cnt == 0)  /* EOF */
			return 0;
		else
			rp->rio_bufptr = rp->rio_buf; /* reset buffer ptr */
	}

	/* Copy min(n, rp->rio_cnt) bytes from internal buf to user buf */
	cnt = n;
	if (rp->rio_cnt < n)
		cnt = rp->rio_cnt;
	memcpy(usrbuf, rp->rio_bufptr, cnt);
	rp->rio_bufptr += cnt;
	rp->rio_cnt -= cnt;
	return cnt;
}
/* $end rio_read */

/*
* rio_readinitb - Associate a descriptor with a read buffer and reset buffer
*/
/* $begin rio_readinitb */
void rio_readinitb(rio_t *rp, int fd)
{
	rp->rio_fd = fd;
	rp->rio_cnt = 0;
	rp->rio_bufptr = rp->rio_buf;
}
/* $end rio_readinitb */

/*
* rio_readnb - Robustly read n bytes (buffered)
*/
/* $begin rio_readnb */
ssize_t rio_readnb(rio_t *rp, void *usrbuf, size_t n)
{
	size_t nleft = n;
	ssize_t nread;
	char *bufp = (char *)usrbuf;

	while (nleft > 0) {
		if ((nread = rio_read(rp, bufp, nleft)) < 0) {
			if (errno == EINTR) /* interrupted by sig handler return */
				nread = 0;      /* call read() again */
			else
				return -1;      /* errno set by read() */
		}
		else if (nread == 0)
			break;              /* EOF */
		nleft -= nread;
		bufp += nread;
	}
	return (n - nleft);         /* return >= 0 */
}
/* $end rio_readnb */

/*
* rio_readlineb - robustly read a text line (buffered)
*/
/* $begin rio_readlineb */
ssize_t rio_readlineb(rio_t *rp, void *usrbuf, size_t maxlen) /* 读取一行数据 */
{
	int n, rc;
	char c, *bufp = (char *)usrbuf;

	for (n = 1; n < maxlen; n++) {
		if ((rc = rio_read(rp, &c, 1)) == 1) {
			*bufp++ = c;
			if (c == '\n')
				break;
		}
		else if (rc == 0) {
			if (n == 1)
				return 0; /* EOF, no data read */
			else
				break;    /* EOF, some data was read */
		}
		else
			return -1;	  /* error */
	}
	*bufp = 0;
	return n;
}
/* $end rio_readlineb */

/**********************************
* Wrappers for robust I/O routines
**********************************/
ssize_t Rio_readn(int fd, void *ptr, size_t nbytes)
{
	ssize_t n;

	if ((n = rio_readn(fd, ptr, nbytes)) < 0)
		unix_error("Rio_readn error");
	return n;
}

void Rio_writen(int fd, void *usrbuf, size_t n)
{
	if (rio_writen(fd, usrbuf, n) != n)
		unix_error("Rio_writen error");
}

void Rio_readinitb(rio_t *rp, int fd)
{
	rio_readinitb(rp, fd);
}

ssize_t Rio_readnb(rio_t *rp, void *usrbuf, size_t n)
{
	ssize_t rc;

	if ((rc = rio_readnb(rp, usrbuf, n)) < 0)
		unix_error("Rio_readnb error");
	return rc;
}

ssize_t Rio_readlineb(rio_t *rp, void *usrbuf, size_t maxlen)
{
	ssize_t rc;

	if ((rc = rio_readlineb(rp, usrbuf, maxlen)) < 0)
		unix_error("Rio_readlineb error");
	return rc;
}

/********************************
* Client/server helper functions
********************************/
/*
* open_clientfd - open connection to server at <hostname, port>
*   and return a socket descriptor ready for reading and writing.
*   Returns -1 and sets errno on Unix error.
*   Returns -2 and sets h_errno on DNS (gethostbyname) error.
*/
/* $begin open_clientfd */
int open_clientfd(char *hostname, int port)
{
	int clientfd;
	struct hostent *hp;
	struct sockaddr_in serveraddr;

	if ((clientfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
		return -1; /* check errno for cause of error */

				   /* Fill in the server's IP address and port */
	if ((hp = gethostbyname(hostname)) == NULL)
		return -2; /* check h_errno for cause of error */
	bzero((char *)&serveraddr, sizeof(serveraddr));
	serveraddr.sin_family = AF_INET;
	bcopy((char *)hp->h_addr_list[0],
		(char *)&serveraddr.sin_addr.s_addr, hp->h_length);
	serveraddr.sin_port = htons(port);

	/* Establish a connection with the server */
	if (connect(clientfd, (SA *)&serveraddr, sizeof(serveraddr)) < 0)
		return -1;
	return clientfd;
}
/* $end open_clientfd */

/*
* open_listenfd - open and return a listening socket on port
*     Returns -1 and sets errno on Unix error.
*/
/* $begin open_listenfd */
int open_listenfd(int port)
{
	int listenfd, optval = 1;
	struct sockaddr_in serveraddr;

	/* Create a socket descriptor */
	if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) /* 居然没有使用包裹函数 */
		return -1;

	/* Eliminates "Address already in use" error from bind. */
	if (setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR,
		(const void *)&optval, sizeof(int)) < 0) /* 设置端口复用 */
		return -1;

	/* Listenfd will be an endpoint for all requests to port
	on any IP address for this host */
	bzero((char *)&serveraddr, sizeof(serveraddr));
	serveraddr.sin_family = AF_INET;
	serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);
	serveraddr.sin_port = htons((unsigned short)port);
	if (bind(listenfd, (SA *)&serveraddr, sizeof(serveraddr)) < 0) /* 绑定 */
		return -1;

	/* Make it a listening socket ready to accept connection requests */
	if (listen(listenfd, LISTENQ) < 0) /* 监听 */
		return -1;
	return listenfd; /* 返回监听套接字 */
}
/* $end open_listenfd */

/******************************************
* Wrappers for the client/server helper routines
******************************************/
int Open_clientfd(char *hostname, int port)
{
	int rc;

	if ((rc = open_clientfd(hostname, port)) < 0) {
		if (rc == -1)
			unix_error("Open_clientfd Unix error");
		else
			dns_error("Open_clientfd DNS error");
	}
	return rc;
}

int Open_listenfd(int port)
{
	int rc;

	if ((rc = open_listenfd(port)) < 0)
		unix_error("Open_listenfd error");
	return rc;
}
/* $end csapp.c */




